TACR1 and amyotrophic lateral sclerosis: These Phox2a cells presumably correspond to the neurokinin 1 receptor (NK1r) -expressing neurons in laminae III and IV that were described in early immunohistochemical studies of rat spinal cord42,43 and subsequently shown to be ALS projection cells.3,7,8,44–47 However, in the mouse many of these cells lack the NK1r.6 Most of the Phox2a cells in lamina V that had numerous contacts from CGRP/SP and NPY axons had at least one dorsally directed dendrite, and in some cases (16/37, 43%) dendrites could be followed into the SDH (Figure 2(d)).